Apparatus for converting petroleum hydrocarbons



July 4,' 1933. w. M. CROSS APPARATUS FOR GONVERTING PETROLEUMHYDROCARBONS Filed Sept. 5. 1925 INVENTOR.

/ wiel-MSS- A TTOW Patented July 4, 1933 UNITED STATES TENT FMEWALTERgM. CROSS, OF KANSAS CITY, MISSOURI, ASSIGNOR, BY IWIESNEASSIGNMENTS,

TO GASOLINE PRODUCTS COMPANY, INC.,

vTION F DELAWARE 0F WILMINGTON, DELAWARE, A CGRPORA- APPARATUS FORGONVERTING PETROLEUM HYDROCARBONS Application filed September Thisinvention relates to improvements in a process and apparatus forconverting petroleum hydrocarbons, and refers more particularly to aprocess in which relatively high boiling point oils are converted tooils of a lower boiling point, such as motor fuels having thecharacteristics of gasoline and the like.

Among the advantages of this construction are, to provide a process inwhich the oil is maintained at cracking conditions of temperature andpressure until a substantial portion ofthe oil has been converted,producing a synthetic crude or crude equivalent having a considerableportion thereof comprising low boiling point hydrocarbons; to providel aprocess in which this synthetic crude, while in a highly heatedcondition, is introduced to an evaporating stage at a reduced pressureat which time the lighter fractions in the oil evaporate olf in the formof vapors'which are fractionated and finally condensedv to produce agasoline distillate while the reflux condensate is returned and reboiledor redistilled by utilization of the heat of the hotter vapors in theevaporating stage; to provide an apparatus for carrying out the processhereinafter described in more detail.

The single figure is a side elevational view with parts in section andparts broken away.

Referring to the drawing, at 1 is shown a furnace in the uppercompartment of which are positioned'preheating tubes 2, whileV in thelower compartment are the heating tubes 3. The tubes in the separatecompartments are connected up by line l to produce a continuous passageof the oil through the heat ing stage. yAt 5 is shown a reaction chamberheavily insulated to prevent loss of heat by radiation. This reactionchamber is preferably forged froma single ingot of steel to produce a.receptacle or chamber adapted to withstand high pressuresiat hightemperatures. `The chamber has removable end openings by means of whichit may be cleaned from time to time of deposited car- VbonY whichaccumulates during the conversion or cracking of the oil. The chamber 5is connectedA by means of a ltransfer line 6 to 3, 1925. Serial No.54,271.

the discharge end of the heating tubes 3 and similarly, by means of atransfer line 7, to the tower 8. A reduction valve 9 is interposed inthe transfer line 7.

The tower consists of a lower evaporating zone 10 inthe upper portion ofwhich is positioned a layer or zone of dispersing material 11, such asmetal lath, Raschig rings or other broken up ceramic material inert tothe action of the hydrocarbon vapors. J ust above this dispersing zonethrough which the vapors must pass as they riseupwardly through thetower is a spray pipe 12 through which the condensate is returned fromthe upper fractionating stage to the lower evaporatlng stage forredistillation. The tower is divided centrally by means of a horizontaldivision plate 13 which is perforated to receive the vertical standpipes14. The vapors on rising through the tower pass from the evaporatingZone through the dispersing zone and through the standpipes 14 to thefractionating stage 15 which consists of a plurality of trays 16 holdingbubble risers 17 surmounted by caps 18 as inthe usual type of bubbletower construction, the latter serving to reverse the flow of thevapors' and cause them to percolate through the pools of oil maintainedupon the separate trays. Arranged on the side of the tower, and adjacentthe upper ends of the standpipes 14, is a liquid level regulating device18 which functions to maintain a pool of condensate upon the lowercompartment plate 13, keeping the standpipes immersed in oil in orderthat a portion of the heat of the vapors passing therethrough will betransferred to the liquid pool surrounding the pipes. This liquid levelregulating device controls a Valve 19 in the drawo line 20 from thislower pool. The line 2O communicates with'a cooler 21 through which theliquid is passed and cooled by being brought into heat exchangerelationship with afcooling medium introduced to the shell of the coolerthrough the line Q2 and discharged'through the pipe 23. The cool liquidpassing from the opposite end of the cooler is directed through the line24 and is distributed in the dispersing stage of the evaporating stageor on to the metal lath or broken up packing material 11 in theevaporating stage. A by-pass line controlled by a valve 26 serves toby-pass the cooler ii' desired. By manipulation ot tie valves 26 in 1theby-pass line and valves 27 and 28 in the line 24, the reflux materialmay be directed through a return line 29 and recycled by means of thepump 30 back through the heating coil or by regulation of the valve 31in the line 29 and valve 32 in the line 33 the reflux condensate may bedrawn from the system.

In the top of the tower is a preheating coil 34. rIhe overhead vaporline 35 communicates with a coil 36 positioned in the condenser boX37,-the discharge end of the cooling coil terminating in a line 38 whichleads to a gas separator 39the latter being equipped with a liquiddrawoli line 40 controlled by a valve 41 and a gas relief line 42controlled by a valve 43. Theunvaporized material from the bottom of thetower is withdrawn automatically through the pipey 44 in which isinterposed the valve 45 controlled by a liquid level regulatingmechanism 46. Steam lines 47 and 48 serve to inject steam into theevaporating and fractionating stages, respectively.

In operation, the oil is introduced 'from any convenient source throughthe pipe 49 and charged, by means of a pump 50, through the preheatingcoil 34 and line 51 to the heating coil 2, thence through the heatingcoil 3 where it receives its cracking heat prior to being dischargedthrough the transfer line 6 into the reaction chamber 5. Thetemperatures in the heating and reaction stages range from 550O to 1000oF., while sutlicient pressure is maintained upon the cracking stages tomaintain the oil substantially in liquid phase, normal operatingpressures ranging from 450 to 1500 pounds per square inch. The velocityof circulation ot the oil through the heating coil is so controlled thatdeposition of carbon is substantially eliminated in the heating stage.

The oil discharged from the reaction chamber through the transfer line 7is introduced at a reduced pressure to the lower or evaporating sectionof the tower 8. Due to the reduced pressure and the contained heat otthe oil, the lighter fractions immediately evaporate ott, the vaporsbeing dispersed in the stage 11, containing metal lath or broken upmaterial. This dispel-sing stage serves to separate out a greaterportion of the entrained liquid in the forni of oil globules whichcontaminate the vapors and produce an excessive load upon thetractionating equipment. The vapors, in this stage, also are subjectedto a partial refluxing action due to the introduction of relativelycooler reflux condensate with which the vapors are brought into intimatecontact. Passing from the evaporating stage, the vapors rise through thestandpipcs 14 and pass thence through the series of evaporating pools inthe bubble tower portion ot the tower. In their passage through thesepools, the higher boiling 'fractions are separated out in the form ofcondensate which is drained back into a lower pool surrounding thestandpipes 14 and maintained at a constant level by means of a liquidlevel regulating device 18. As described, this condensate is withdrawnand passed through the cooler 21 to be returned to the evaporatingstage, or is recycled through the line 29 to the heating coil or removedfrom the system through the line 33. The vapors still uncondensed, whicharrive at the top ot the tower, are subjected to additional refluxcondensation due to their being brought into contact with the preheatingcoil 34 through which is circulated the cool charging stock. Vaporsremaining uncondensed in the tower pass oil through the line 35 and aresubjected to iinal condensation in the cooling coil 36 after which theliquid distillate is discharged into the gas separator where theiucondensible gases are removed from the liquid distillate.

As described, the cracking portion of the system is maintained underrelatively high pressure, while the evaporating and fractionatingequipment are maintained under substantially atmospheric pressure. Theutilization ot' a single tower to take the place of a double towerconstruction, i. e., a separate evaporating and tractionating towerconnected by numerous lines and valves, supplies not only a compact,etlicient arrangement, but eliminates considerable expense in thenecessary pipes and tittings which must be used in connecting up asystem having a double tower arrangement. Furthermore, better heateconomy can be practiced in a system of this type.

I claim as my invention:

1. An apparatus for conversion of hydrocarbon oils comprising incombination a cracking coil, a reaction chamber, and a tower having anevaporating zone in the lower portion thereoi" and a fractionating zonein the upper portion thereof', means for passing the. oil undersupcratmospheric pressure through said cracking coil into said reactionchamber, means including a pressure reducing valve for passing oil fromsaid reaction chamber into the evaporating Zone of said tower, means formaintaining the level ot liquid in said evaporatingzone below the pointof entrance of cracked products into said Zone, a packing for saidevaporatingl zone located above the point of introduction of saidproducts, a partition across said tower forming a vapor space above saidpacking, a plurality of stand pipes piercing said partition andprojecting above the level thereof, bubble trays above the upper end ofsaid stand pipes for tractionating vapors rising tlnougli said standpipes to form a desired distillate and a reflux condensate, means formaintaining a pool of reflux condensate be-V amount of condensate sosprayed into said 2. An apparatus in accordance with .claim l whereinmeans is provided for returnlng to said cracking coil condensateWithdrawn from said pool.

WALTER M. CROSS.Y

